Sarı Ayşe Nur, Süzük Serap, Karatuna Onur, Öğünç Dilara, Karakoç Ayşe Esra, Çizmeci Zeynep, Alışkan Hikmet Eda, Cömert Füsun, Bakıcı Mustafa Zahir, Akpolat Nezahat, Çilli Fatma Feriha, Zer Yasemin, Karataş Aysel, Akgün Karapınar Bahar, Bayramoğlu Gülçin, Özdamar Melda, Kalem Fatma, Delialioğlu Nuran, Aktaş Elif, Yılmaz Nisel, Gürcan Şaban, Gülay Zeynep
Dokuz Eylul University Faculty of Medicine, Department of Medical Microbiology, Izmir, Turkey. SANKO University Faculty of Medicine, Department of Medical Microbiology, Gaziantep, Turkey.
Mikrobiyol Bul. 2017 Jul;51(3):299-303. doi: 10.5578/mb.57515.
Colistin is a polymyxin antibiotic which is considered as one of the last line agents against infections due to multidrug resistant or carbapenem resistant gram-negative pathogens. Colistin resistance is associated with chromosomal alterations which can usually cause mutations in genes coding specific two component regulator systems. The first plasmid-mediated colistin resistance gene, mcr-1 was described in Escherichia coli and Klebsiella pneumoniae isolates in December 2015 and followed by another plasmid-mediated colistin resistance gene mcr-2 in 2016. The rapid and interspecies dissemination of plasmid-mediated resistance mechanisms through horizontal gene transfer, have made these genes considerably threatening. After the first reports, although mcr-1/mcr-2 producing Enterobacteriaceae isolates have been reported from many countries, there have been no reports from Turkey. Thus, the aim of this study was to investigate the presence of mcr-1/mcr-2 in clinical Enterobacteriaceae isolates from different parts of our country. A total of 329 Enterobacteriaceae isolates from 22 laboratories were collected which were isolated between March, 2015 and February, 2016. mcr-1/mcr-2 were investigated by polymerase chain reaction during February-March, 2016. Two hundred and seventeen of Klebsiella pneumoniae (66%), 75 of Salmonella spp. (22.8%), 31 of Esherichia coli (9.4%), 3 of Enterobacter cloacae (0.9%), 2 of Klebsiella oxytoca (0.6%) and 1 of Enterobacter aerogenes (0.3%) isolates were included to the study. Agarose gel electrophoresis results of PCR studies have shown expected band sizes for positive control isolates as 309 bp for mcr-1 and 567 bp for mcr-2. However, the presence of mcr-1/mcr-2 genes was not detected among the tested study isolates of Enterobacteriaceae. Although mcr-1/mcr-2 were not detected in our study isolates, it is highly important to understand the mechanism of resistance dissemination and determine the resistant isolates by considering that colistin is a last-line antibiotic against infections of multidrug or carbapenem resistant gram-negative bacteria. Thus, it is suggested that these mechanisms should be followed-up in both clinical and non-clinical (e.g. isolates from food animals, raw meats and environment) isolates of special populations.
黏菌素是一种多黏菌素类抗生素，被认为是针对多重耐药或碳青霉烯耐药革兰氏阴性病原体感染的最后一道防线药物之一。黏菌素耐药性与染色体改变有关，这种改变通常会导致编码特定双组分调节系统的基因突变。2015年12月，在大肠杆菌和肺炎克雷伯菌分离株中首次发现了第一个质粒介导的黏菌素耐药基因mcr - 1，随后在2016年又发现了另一个质粒介导的黏菌素耐药基因mcr - 2。通过水平基因转移，质粒介导的耐药机制在种间迅速传播，这使得这些基因具有相当大的威胁性。在首次报道之后，尽管许多国家都报告了产mcr - 1/mcr - 2的肠杆菌科分离株，但土耳其尚未有相关报道。因此，本研究的目的是调查我国不同地区临床肠杆菌科分离株中mcr - 1/mcr - 2的存在情况。共收集了来自22个实验室的329株肠杆菌科分离株，这些分离株是在2015年3月至2016年2月期间分离得到的。2016年2月至3月期间，通过聚合酶链反应对mcr - 1/mcr - 2进行了检测。研究纳入了217株肺炎克雷伯菌（66%）、75株沙门氏菌属（22.8%）、31株大肠杆菌（9.4%）、3株阴沟肠杆菌（0.9%）、2株产酸克雷伯菌（0.6%）和1株产气肠杆菌（0.3%）分离株。PCR研究的琼脂糖凝胶电泳结果显示，阳性对照分离株的预期条带大小为mcr - 1为309 bp，mcr - 2为567 bp。然而，在所检测的肠杆菌科研究分离株中未检测到mcr - 1/mcr - 2基因。尽管在我们的研究分离株中未检测到mcr - 1/mcr - 2，但鉴于黏菌素是针对多重耐药或碳青霉烯耐药革兰氏阴性菌感染的最后一线抗生素，了解耐药性传播机制并确定耐药分离株非常重要。因此，建议在特殊人群的临床和非临床（如来自食用动物、生肉和环境的分离株）分离株中对这些机制进行跟踪监测。
